1. Technical Field
The present invention relates to a method and apparatus for rapidly making, screening, and characterizing an array of materials in which process conditions are controlled and monitored, and in particular where the feed to each reactor vessel is continuously fed.
2. Discussion
Combinatorial materials science generally refers to methods for creating a collection of diverse compounds or materials using a relatively small set of precursors and/or methods for rapidly testing or screening the collection of compounds or materials for desirable performance characteristics and properties. As currently practiced, combinatorial materials science permits scientists to systematically explore the influence of structural variations in candidates by dramatically accelerating the rates at which they are created and evaluated. Compared to traditional discovery methods, combinatorial methods sharply reduce the costs associated with preparing and screening each candidate.
Combinatorial chemistry has revolutionized the process of drug discovery. See, for example, 29 Acc. Chem. Res. 1–170 (1996); 97 Chem. Rev. 349–509 (1997); S. Borman, Chem. Eng. News 43–62 (Feb. 24, 1997); A. M. Thayer, Chem. Eng. News 57–64 (Feb. 12, 1996); N. Terret, 1 Drug Discovery Today 402 (1996)). One can view drug discovery as a two-step process: acquiring candidate compounds through laboratory synthesis or through natural product collection, followed by evaluation or screening for efficacy. Pharmaceutical researchers have long used high-throughput screening (HTS) protocols to rapidly evaluate the therapeutic value of natural products and libraries of compounds synthesized and cataloged over many years. However, compared to HTS protocols, chemical synthesis has historically been a slow, arduous process. With the advent of combinatorial methods, scientists can now create large libraries of organic molecules at a pace on par with HTS protocols.
Recently, combinatorial approaches have been used for discovery programs unrelated to drugs. For example, some researchers have recognized that combinatorial strategies also offer promise for the discovery of inorganic compounds such as high-temperature superconductors, magnetoresistive materials, luminescent materials, and catalytic materials. See, for example, U.S. Pat. No. 5,776,359, as well as U.S. patent application Ser. No. 08/327,513 “The Combinatorial Synthesis of Novel Materials” (published as WO 96/11878) and co-pending U.S. patent application Ser. No. 08/898,715 “Combinatorial Synthesis and Analysis of Organometallic Compounds and Catalysts” (published as WO 98/03251), which are each herein incorporated by reference.
Because of its success in eliminating the synthesis bottleneck in drug discovery, many researchers have come to narrowly view combinatorial methods as tools for creating structural diversity. Few researchers have emphasized that, during synthesis, variations in temperature, pressure and other process conditions can strongly influence the properties of library members. For instance, reaction conditions are particularly important in formulation chemistry, where one combines a set of components under different reaction conditions or concentrations to determine their influence on product properties. Moreover, it is often beneficial to mimic industrial processes that are different than in pharmaceutical research so that many workers have failed to realize that processes often can be used to distinguish among library members. Some parallel reactors are known; see for example WO 98/36826 and U.S. Pat. Nos. 4,099,923 and 4,944,923, that are each incorporated herein by reference. However, what is needed is an apparatus for preparing and screening combinatorial libraries in which an industrial process can be followed.